The present invention relates to gas turbine engines for aircraft and, more particularly, to the engine housing of a gas turbine engine in which the fan outer nacelle and auxiliary support frame are each segmented into two 180 degree segments to allow for easy removal and installation of the thrust producing section of a large turbine engine.
Gas turbine engines for commercial aircraft generally have become increasingly larger with each generation of new aircraft. Some of the size increase is attributable to the need for increased power output of a turbofan engine in order to power larger aircraft. Some size increase is also attributable to the desire for more fuel-efficient engines achievable by increasing the engine bypass ratio. A higher bypass ratio requires a larger fan and a correspondingly larger diameter nacelle structure. Present generation aircraft gas turbine engines with high bypass ratios may have nacelle diameters in the range of twelve feet. Not only does this large engine create a clearance concern for under-wing mounting, but it also presents a concern for installation and removal on a timely basis for service.
U.S. patent application Ser. No. 765,804 entitled "Structure for Eliminating Lift Load Bending in Engine Core of Turbofan" filed Sep. 26, 1991, discloses a novel nacelle and frame mounting structure which is designed to prevent the engine core in a turbofan engine from experiencing large bending loads generated by inlet lift loads. This novel nacelle structure comprises a load carrying nacelle for efficient load transfer. The nacelle structure is capable of transferring loads directly from the inlet to the attaching pylon and isolating the engine gas generator from the load path. For such a nacelle structure, engine service requires detachment of the nacelle from the engine frame mount and removal of the fan blades. The outlet guide vane (OGV) assembly must also be removed after which the gas generator can be floated away to the aft of the nacelle structure.
Since time is of the essence when engine replacement is necessitated (usually overnight placement being desired), it is important that measures be taken to insure that quick engine replacement and maintenance are realized. Therefore, a need exists for a nacelle structure which would make the easy maintenance and replacement of large turbofan engines possible, including those engines which have a nacelle structure designed to prevent core bending of the engine.